At the second presidential debate on Sunday, Donald Trump vowed that if he's elected president, he would have a special prosecutor investigate Hillary Clinton.

On America's Newsroom today, Judge Andrew Napolitano said that President Trump could have the Justice Department reopen the closed investigation into Clinton's private email server, and it would not require a special prosecutor.

"He could have his own attorney general reopen the investigation and assign a new team of people to examine the same evidence and look at it differently, the way the president - if he's president - wants it looked at," Napolitano explained.

He said that if Trump wants a special prosecutor to investigate the FBI's investigation itself, on the other hand, that would be "very serious and substantive."

Napolitano explained that the FBI's investigation was "so flawed," as it failed to use all the tools that were at the agency's disposal and it ignored a "mountain of evidence."

"The evidence of her guilt is overwhelming. It was obviously a policy decision by the White House not to investigate her."

Napolitano suggested that Trump used the term "special prosecutor" at the debate to gin up his base, since such an appointment would not be necessary to open an investigation into the Clinton investigation.

"There's a great many people who feel the way I do, that she got off because her last name is Clinton. And something is wrong with the rule of law when that can happen."

House Intelligence Committee Chairman Adam Schiff of California said that "people have suffered enough" because of President Trump and that a real leader would re-open the part of the government that has been shuttered since December.